Minecraft Crashes After Hitting A Player

Let's say i'm on a server, kay? Then i play Skywars, kay? Well, the issue here is that when i hit a player it crashes my minecraft inmediately. I have tried everything; i uninstalled Minecraft and re-installed it, i have updated my Optifine version, too. I did something to make my F's work but nothing. I tried changing the F's controls for letters, just to make it work; like F5, i changed it to the letter I, I updated Java (and by that i mean install it again). If you could help me pls i would appreciate it.